It cracked the skull of 73-year-old William Horner like an eggshell, spattering blood all over his junk shop at 213 N. Broad St.

He was already dying in a back room, amid the used furniture and knickknacks, when the Trenton police got there. Up front, the old man's common-law wife lay groaning, also clubbed over the head.

She survived to tell cops the story. Some black men had come to the store, saying they wanted to buy a mattress and stove. Then came the brutal attack -- all for $50.

What happened in that cluttered little shop on Jan. 27, 1948, would turn into Trenton's most controversial whodunit: the "Trenton Six" case.

They were six African-Americans on trial for murdering a white man. Guilty or innocent? The question divided law-and-order men from civil rights crusaders, anti-communists from liberals, blacks from whites.

Around the world, the trial of the Trenton Six made headlines and stirred passions. On its outcome hinged not just six men's lives, but also, in the opinion of many, the very fairness of the American justice system.

Before there was a Trenton Six case, however, there was just confusion and fright.

The police didn't even know how many men had committed the deadly robber. The dead man's wife, Elizabeth Horner, saw three. Another witness saw two light-skinned black men walking away from the store in the minutes after the robbery. Yet another witness saw three black "teenagers" running toward a car, driven by a fourth man.

The pressure was tremendous to solve the case. Even the normally sedate Trenton Evening Times cried bloody murder. On Jan. 29, it ran an editorial, "The Idle Death Chair," bemoaning the fact that New Jersey was going soft on snuffing out the lives of killers.

Up and down Spring Street, Battle Monument and other black neighborhoods, police patrols pulled over black men for random questioning. On Feb. 6, they made a catch. His name was Collis English, and he was pulled over for driving his dad's car without permission.

The 23-year-old English disappeared into police custody for four days. When he finally emerged Feb. 11, it was to be arraigned on capital murder charges in the death of the North Broad Street junkman.

Charged along with English were five other men. One of them, 35-year-old McKinley Forrest, was a brother-in-law of English. He had come to police headquarters a few days earlier to find out why his friend was being held; then he found himself under interrogation for the killing too.

The rest of the Trenton Six were named in the confessions signed by Forrest and English. They were Ralph Cooper, 23; John McKenzie, 24; James Thorpe, 24; and Horace Wilson, 40. All but Wilson ended up signing confessions, too.

But there was something incredibly fishy about these confessions.

"You didn't have to be very smart to recognize what it was," said Ruth Rabstein, a lawyer who would later serve on the team defending English. "It was a manufactured case. They had the wrong people, pure and simple."

English, a Navy veteran with a rheumatic heart and mental slowness, quickly recanted. The confession was fake, he said, forced out of him by threats and being deprived of sleep for days on end.

He'd had a record of babbling whatever someone wanted to hear. "Some neighbor of his on Church Street once told me she'd accused him of stealing pies off her windowsill," Rabstein said. "He said he did it, but she later found out it was someone else entirely."

And there was more, much more, that threw severe doubt onto the state's case against the Trenton Six:

* McKinley Forrest signed a "confession" to swinging the bottle that killed Horner. The cops also produced a receipt with his signed name, showing he had been in Horner's store a week before. But Forrest was illiterate -- and marked his name with an "X."

* Mrs. Horner failed to identify any of the Trenton Six at the station house, but she later ID'd them from photos.

* Wilson was working on a Robbinsville potato farm the morning of the murder, and had work logs to prove it. Forrest, McKenzie and Cooper had alibis too.

* Thorpe had only one arm -- and that arm had been amputated because of a car accident eight days before the murder. No witnessed remembered anything so striking as a one-armed man.

* The witness who saw a getaway by three "teenagers" described the escape car as a green Plymouth. English's car, the one police claimed was used in the robbery, was a black Ford.

Nevertheless, the prosecution insisted the Trenton Six were guilty. So guilty, of so cold-blooded a deed, that the death penalty was called for.

The evidence was "overwhelming," said Mercer County Prosecutor Mario Volpe, a passionate orator often talked about as a future candidate for governor. As for the denials of the confessions, the defendants actually "agreed and planned to act crazy in order to produce or provide an avenue of escape," he said.

An all-white jury deliberated the case for 7 1/2 hours and came back with its verdict Aug. 6: guilty.

The judge immediately sentenced all six defendants to death in the electric chair. Off they went, to New Jersey State Prison's Death Row, and there they might have been electrocuted had it not been for English's sister, Bessie Mitchell.

Mitchell, a New York City seamstress, saw the verdict as a gross miscarriage of justice and petitioned Trenton's NAACP to raise money for an appeal. The local group declined, seeing it as an unpopular and losing case.

So she turned to the Communist Party. "God knows we couldn't be no worse off than we are now," she explained.

The Communist Party, through its legal arm, the Civil Rights Congress, generated the publicity the Trenton Six needed. It printed a pamphlet on the case: "Lynching, Northern Style." The cover featured a cartoon of a judge looking on approvingly as six black man hanged from the bar of justice.

Commentators around the world compared the Trenton Six to the Scottsboro Boys, a group of young black men in Alabama who'd been convicted -- then cleared -- of a rape on the flimsiest of evidence.

A paper in London headlined the Trenton story: "THEY MUST DIE FOR BEING BLACK."

In 1949, the Trenton Six murder conviction was reversed by the New Jersey Supreme Court, which found that the jury had made a serious blunder: it had never specified what degree of murder the men were guilty of. The judge had simply assumed first degree, and so sentenced the men to die.

A new defense team would be led by George Pellettieri, and impassioned Trenton labor lawyer, and a battery of NAACP and civil rights attorneys from New York and Philadelphia. Ruth Rabstein was Pellettieri's assistant counsel; working on this case and many others together, they would fall in love and marry.

The Communist Party quietly bowed out of the Trenton Six defense, Rabstein recalled. War in Korea and Joe McCarthy's Red-hunting crusade were making life tough on the communists, and the Trenton Six would only suffer for the connection.

"We thought, we really did, that we had the chance to save the lives of some innocent people," said Rabstein, who is now 86 and living in Princeton. "The communists were diverting attention to make their own, political points."

The new trial began in March 1951. Every prosecution witness was met by a rebuttal witness; every prosecution argument had a counter-argument.

The jury foreman in the second trial was Edward Kerr, a Trenton postal clerk and World War II veteran. He is now 77 and vividly remembers being sequestered for 13 long weeks at the Hotel Hildebrecht, gaining a "lot of flab" from eating desserts that the petite women jurors refused.

The jury Kerr served on was all-white like the first one that had doomed the Trenton Six to die. But this time around, Kerr and his fellow jurors were troubled by the prosecution's case.

They deliberated from evening until 6 a.m. at the courthouse, taking ballot after ballot. Most jurors wanted to free at least some of the six, but couldn't agree on which ones.

"I didn't know how it ever got to be murder one," said Kerr, now of Hamilton. "There were a lot of problems with the confessions.

"It was unfair to put all six of them away. Yet there was some circumstantial evidence that linked at least two of them to the crime scene ... and so we found a happy medium."

Kerr read the jury's compromise verdict on June 14. For English and Cooper, guilty, with a recommendation of mercy.

For the remaining four of the Trenton Six: not guilty.

Whoops rang out through the courtroom. Yet the defense was not totally pleased.

Pellettiteri immediately launched an appeal, noting that since the prosecution alleged all six men to be present at the time of the robbery, the jury could not find some of them innocent and some guilty.

Then, fate intervened.

English's bad heart finally gave out after another year in prison, and he died at age 27. Cooper, wearying of the legal maneuvering, copped a plea to murder -- in which he implicated all five of his co-defendants -- and agreed to a sentence of time already served. He was paroled in 1954.

None of the Trenton Six is still alive. None of them lived even to be 65 years old. Thorpe, the one-armed man, was the last to die -- about 10 years ago, Rabstein remembered.

The Trenton Six case left lessons for a generation of civil rights activists.

Catherine Graham, who went on to become Trenton's NAACP chief and a Democratic Party leader, said she was one of many young people outraged by the death sentence.

"Today, the police may try to get away with pinning something on you just because you're black," she said. "But we're less likely to stand for it."

As for Kerr, the jury foreman who read the last "not guilty" verdicts, the case showed him the criminal justice system could absorb a tough body blow.

"What we wanted was a just verdict," he said. "And what I learned was that an injustice doesn't go too far without someone or something straightening it out."